Poly water vapor permeability

Multilayered materials owe their properties and behavior to the properties of and the interactions between the components (5). Each of the two or more components contributes its particular property to the total performance of the multilayered material. For example, in Pouch 1, Table II, the aluminum foil provides high oxygen and water vapor permeability resistance, poly (ethylene terephthalate) provides structural strength and stiffness, and the ethylene-butene copolymer provides a heat sealable layer. If the components of the multilayered materials interact then the whole would be something different than the sum of its parts. In other words, the properties of the components of the multilayered materials are not independent of one another but rather are interdependent. 

The concept of lower water vapor permeability has been tested in comparison to a silicone based RTV-2 system (Elastosil SG 500 from Wacker Silicones) according to DIN 53122-1 (samples were 2 mm thick). The Poly bd RT 45 HTLO-based sample also contained ground calcium carbonate as a filler. It can be clearly seen that the overall permeability is significantly lower for the novel RTV-2 system. 

Tsuji, H., Okino, R., Daimon, H. and Fujie, K. (2006) Water vapor permeability of poly(lactide)s Effects of molecular characteristics and crystaUinity. Journal of Applied Polymer Science, 99,2245-2252. 

Tsuji, H. and Tsuruno, T. (2010) Water vapor permeability of poly(L-lactide)/poly(D-lactide) stereocomplexes. Macromolecular Materials and Engineering, 295, 709-715. 

Uemura, Y., Maetsuru, Y.-S., Fujita, T. et al. (2006) The effect of coatings formed by low temperature tetramethoxysilane plasma treatment on water-vapor permeability of poly(L-lactic acid) film. Korean Journal of Chemical Engineering, 23, 144-147. 

The polymerization proceeds via living diradicals. Poly(/ -xylylene), poly(2-chloro-p-xylylene), and poly(2,5-dichloro-/>-xylylene) are produced commercially by direct polymerization of the monomer on the surface to be coated. The films, which have only slight gas and water vapor permeability, are mostly used to separate condensor plates. 

H. Tsuji, R. Okino, H. Daimon and K. Fujie, Water vapor permeability of poly (lactide)s effects of molecular characteristics and crystallinity, J. Appl. Polym. Sci., 99 (2006) 2245-2252. 

Transport in semi-crystalline polymers can, thus, be treated on the basis of a simple two phase model, consisting of a dispersed impermeable crystalline phase in a permeable amorphous matrix. Lasoski and Cobbs (12) attempted to correlate the solubility of water vapor in unoriented poly(ethylene terephthalate) and nylon 610 with... 

In spread coating (laquering), solutions of film-forming polymers are applied and the solvent allowed to evaporate. Metallic and nonmetallic components and films of cellulose or aluminum are lacquered. Lacquered cellulose films are less permeable to water vapor, but poly(ethylene)-bonded films compete with these on the market (Section 12.2.6). Paints and lacquers... 

Zhang et al [66] produced a superhydrophobic surface by the simple mechanical extension of a poly(tetrafluoroethylene) (PTFE) film. The fibriUar structure, a consequence of cavitation during deformation, resulted in contact angles larger than 150°. This structure, which is similar to the well-known Gore-Tex membrane, is best known for its use as a textile that is permeable to water vapor but not liquid water. However, these membranes are essentially fibrillar networks that are fundamentally different from the nonwoven fibrous textiles such as those formed by electrospinning. 

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